<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Service
 * @subpackage ReCaptcha
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */

/** @see Zend_Service_ReCaptcha */
require_once 'Zend/Service/ReCaptcha.php';

/**
 * Zend_Service_ReCaptcha_MailHide
 *
 * @category   Zend
 * @package    Zend_Service
 * @subpackage ReCaptcha
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: MailHide.php 16971 2009-07-22 18:05:45Z mikaelkael $
 */
class Zend_Service_ReCaptcha_MailHide extends Zend_Service_ReCaptcha
{
	/**#@+
	 * Encryption constants
	 */
	const ENCRYPTION_MODE = MCRYPT_MODE_CBC;
	const ENCRYPTION_CIPHER = MCRYPT_RIJNDAEL_128;
	const ENCRYPTION_BLOCK_SIZE = 16;
	const ENCRYPTION_IV = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
	/**#@-*/

	/**
	 * Url to the mailhide server
	 *
	 * @var string
	 */
	const MAILHIDE_SERVER = 'http://mailhide.recaptcha.net/d';

	/**
	 * The email address to protect
	 *
	 * @var string
	 */
	protected $_email = null;

	/**
	 * Binary representation of the private key
	 *
	 * @var string
	 */
	protected $_privateKeyPacked = null;

	/**
	 * The local part of the email
	 *
	 * @var string
	 */
	protected $_emailLocalPart = null;

	/**
	 * The domain part of the email
	 *
	 * @var string
	 */
	protected $_emailDomainPart = null;

	/**
	 * Local constructor
	 *
	 * @param string $publicKey
	 * @param string $privateKey
	 * @param string $email
	 * @param array|Zend_Config $options
	 */
	public function __construct($publicKey = null, $privateKey = null, $email = null, $options = null)
	{
		/* Require the mcrypt extension to be loaded */
		$this->_requireMcrypt();

		/* If options is a Zend_Config object we want to convert it to an array so we can merge it with the default options */
		if ($options instanceof Zend_Config) {
			$options = $options->toArray();
		}

		/* Merge if needed */
		if (is_array($options)) {
			$options = array_merge($this->getDefaultOptions(), $options);
		} else {
			$options = $this->getDefaultOptions();
		}

		parent::__construct($publicKey, $privateKey, null, $options);

		if ($email !== null) {
			$this->setEmail($email);
		}
	}

	/**
	 * See if the mcrypt extension is available
	 *
	 * @throws Zend_Service_ReCaptcha_MailHide_Exception
	 */
	protected function _requireMcrypt()
	{
		if (!extension_loaded('mcrypt')) {
			/** @see Zend_Service_ReCaptcha_MailHide_Exception */
			require_once 'Zend/Service/ReCaptcha/MailHide/Exception.php';

			throw new Zend_Service_ReCaptcha_MailHide_Exception('Use of the Zend_Service_ReCaptcha_MailHide component requires the mcrypt extension to be enabled in PHP');
		}
	}

	/**
	 * Serialize as string
	 *
	 * When the instance is used as a string it will display the email address. Since we can't
	 * throw exceptions within this method we will trigger a user warning instead.
	 *
	 * @return string
	 */
	public function __toString()
	{
		try {
			$return = $this->getHtml();
		} catch (Exception $e) {
			$return = '';
			trigger_error($e->getMessage(), E_USER_WARNING);
		}

		return $return;
	}

	/**
	 * Get the default set of parameters
	 *
	 * @return array
	 */
	public function getDefaultOptions()
	{
		return array(
            'linkTitle'      => 'Reveal this e-mail address',
            'linkHiddenText' => '...',
            'popupWidth'     => 500,
            'popupHeight'    => 300,
		);
	}

	/**
	 * Override the setPrivateKey method
	 *
	 * Override the parent method to store a binary representation of the private key as well.
	 *
	 * @param string $privateKey
	 * @return Zend_Service_ReCaptcha_MailHide
	 */
	public function setPrivateKey($privateKey)
	{
		parent::setPrivateKey($privateKey);

		/* Pack the private key into a binary string */
		$this->_privateKeyPacked = pack('H*', $this->_privateKey);

		return $this;
	}

	/**
	 * Set the email property
	 *
	 * This method will set the email property along with the local and domain parts
	 *
	 * @param string $email
	 * @return Zend_Service_ReCaptcha_MailHide
	 */
	public function setEmail($email)
	{
		$this->_email = $email;

		$emailParts = explode('@', $email, 2);

		/* Decide on how much of the local part we want to reveal */
		if (strlen($emailParts[0]) <= 4) {
			$emailParts[0] = substr($emailParts[0], 0, 1);
		} else if (strlen($emailParts[0]) <= 6) {
			$emailParts[0] = substr($emailParts[0], 0, 3);
		} else {
			$emailParts[0] = substr($emailParts[0], 0, 4);
		}

		$this->_emailLocalPart = $emailParts[0];
		$this->_emailDomainPart = $emailParts[1];

		return $this;
	}

	/**
	 * Get the email property
	 *
	 * @return string
	 */
	public function getEmail()
	{
		return $this->_email;
	}

	/**
	 * Get the local part of the email address
	 *
	 * @return string
	 */
	public function getEmailLocalPart()
	{
		return $this->_emailLocalPart;
	}

	/**
	 * Get the domain part of the email address
	 *
	 * @return string
	 */
	public function getEmailDomainPart()
	{
		return $this->_emailDomainPart;
	}

	/**
	 * Get the HTML code needed for the mail hide
	 *
	 * @param string $email
	 * @return string
	 * @throws Zend_Service_ReCaptcha_MailHide_Exception
	 */
	public function getHtml($email = null)
	{
		if ($email !== null) {
			$this->setEmail($email);
		} else if ($this->_email === null) {
			/** @see Zend_Service_ReCaptcha_MailHide_Exception */
			require_once 'Zend/Service/ReCaptcha/MailHide/Exception.php';

			throw new Zend_Service_ReCaptcha_MailHide_Exception('Missing email address');
		}

		if ($this->_publicKey === null) {
			/** @see Zend_Service_ReCaptcha_MailHide_Exception */
			require_once 'Zend/Service/ReCaptcha/MailHide/Exception.php';

			throw new Zend_Service_ReCaptcha_MailHide_Exception('Missing public key');
		}

		if ($this->_privateKey === null) {
			/** @see Zend_Service_ReCaptcha_MailHide_Exception */
			require_once 'Zend/Service/ReCaptcha/MailHide/Exception.php';

			throw new Zend_Service_ReCaptcha_MailHide_Exception('Missing private key');
		}

		/* Generate the url */
		$url = $this->_getUrl();

		/* Genrate the HTML used to represent the email address */
		$html = htmlentities($this->_emailLocalPart) . '<a href="' . htmlentities($url) . '" onclick="window.open(\'' . htmlentities($url) . '\', \'\', \'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=' . $this->_options['popupWidth'] . ',height=' . $this->_options['popupHeight'] . '\'); return false;" title="' . $this->_options['linkTitle'] . '">' . $this->_options['linkHiddenText'] . '</a>@' . htmlentities($this->_emailDomainPart);

		return $html;
	}

	/**
	 * Get the url used on the "hidden" part of the email address
	 *
	 * @return string
	 */
	protected function _getUrl()
	{
		/* Figure out how much we need to pad the email */
		$numPad = self::ENCRYPTION_BLOCK_SIZE - (strlen($this->_email) % self::ENCRYPTION_BLOCK_SIZE);

		/* Pad the email */
		$emailPadded = str_pad($this->_email, strlen($this->_email) + $numPad, chr($numPad));

		/* Encrypt the email */
		$emailEncrypted = mcrypt_encrypt(self::ENCRYPTION_CIPHER, $this->_privateKeyPacked, $emailPadded, self::ENCRYPTION_MODE, self::ENCRYPTION_IV);

		/* Return the url */
		return self::MAILHIDE_SERVER . '?k=' . $this->_publicKey . '&c=' . strtr(base64_encode($emailEncrypted), '+/', '-_');
	}
}